Massive space rock smash-up with Uranus recreated in a riot of colour

Uranus may be the weirdest planet in our solar system, and the most complex simulation ever of its past could help us figure out why.

While most planets in our solar system spin on axes at right angles to the planes of their orbits, Uranus rotates on its side. It could not have formed that way, so most planetary scientists believe that, sometime in its past, a large space rock smashed into it and tipped it over.